async.verify.cpp
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: libcpp-has-no-threads
// UNSUPPORTED: c++03, c++11, c++14, c++17
// <future>
// template <class F, class... Args>
// future<typename result_of<F(Args...)>::type>
// async(F&& f, Args&&... args);
// template <class F, class... Args>
// future<typename result_of<F(Args...)>::type>
// async(launch policy, F&& f, Args&&... args);
#include <future>
#include <atomic>
#include <memory>
#include <cassert>
#include "test_macros.h"
int foo (int x) { return x; }
int main(int, char**)
{
std::async( foo, 3); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
std::async(std::launch::async, foo, 3); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
return 0;
}